This is a really interesting viewpoint on Northern Pelanda. I've been meaning for some time to do something based around the unusual local rules-of-engagement in Human-Tararg waves of afforestation and deforestation where there seem to be well defined refuge areas in which 'defeated' enemies are allowed to congregate under relatively benign oversight of the victors. Much to chew over. The Pyramid of Derdromus at Karresh and it's underworld connection is probably relevant to your 'Greater Spol' cultural area.

There is an 'approved' font for the runes available at
https://www.glorantha.com/docs/glorantha-core-rune-font/
It's going to be updated to include some sorcery practice runes but that hasn't happened yet. There is discussion at

The boards have been down all day in my part of the forest. As Jajagappa said, there's no applicable cannon, but if a Salmon can get Sea Eagle's attention it's very likely to be carried up to the sky world. The trick would be to get free at the right time to land near the top of the Skyfall, (and avoid getting eaten). Ideally you'd leave something better than lunch, to avoid earning Sea Eagle's displeasure.

Alternatively the opposite "we can't be bothered to insult you properly" approach can work. e.g. call someone a stack packer or stork porker instead of a stick picker and and just shrug whatever if they get uptight about it.

There's no mention of zinc in Glorantha as far as I know, I was just speculating that Dwarf brass might not just be a variation of 'air god' bronze. The air gods threw some pretty big wrenches in the world machine, and the dwarves may be looking for an upgrade to replace the faulty components. They are known to produce Iron which no one else understands, maybe they have other secrets.

We're I to be a Mostali, I might well consider that the bronze derived form various storm gods was a substandard material for world machine maintenance and instead synthesise a less unpredictable analogue for it where no other alternative was acceptable. I doubt they approve of all that chthonic tin either.
I like zinc.